Rigorous Coupled-Wave Approach (RCWA) has been used successfully and accurately to study simple grating structures, such as one-layer gratings, one-whole gratings. In this paper, RCWA is expanded to solve Sandwich gra...Rigorous Coupled-Wave Approach (RCWA) has been used successfully and accurately to study simple grating structures, such as one-layer gratings, one-whole gratings. In this paper, RCWA is expanded to solve Sandwich gratings (SG), which is composed of two identical planar dielectric gratings adjoined by thin metallic or dielectric film. The electromagnetic analytic expressions for each layer of SG structure are given and rigorous coupled-wave equations are deduced. The numerical investigations for the diffraction spectra of SG by our theoretical and computer programs are in good agreement with the results of classical RCWA in the condition when a Sandwish grating is simplified to a classical one-layer grating. The calculations by our programs of another condition when a Sandwish grating is degenerated to a classical single planar structure also conform to the results of classical electromagnetic theory. The research results above indicate that the extended theoretical formula has backwards compatibility and is self-consistent with the classical theory.展开更多
In this paper, the intensity distributions of the magnetic field in the proposed sandwich grating were studied. The results indicated that there were two apparent enhanced transmission peaks. The magnetic intensity di...In this paper, the intensity distributions of the magnetic field in the proposed sandwich grating were studied. The results indicated that there were two apparent enhanced transmission peaks. The magnetic intensity distributions of these two peaks manifest that the narrow higher transmission enhancement peak was caused by guided mode resonance and the other wide low one was formed by surface plasmon resonance. The resonant wavelength was estimated by the momentum matching conditions of resonance.展开更多
文摘Rigorous Coupled-Wave Approach (RCWA) has been used successfully and accurately to study simple grating structures, such as one-layer gratings, one-whole gratings. In this paper, RCWA is expanded to solve Sandwich gratings (SG), which is composed of two identical planar dielectric gratings adjoined by thin metallic or dielectric film. The electromagnetic analytic expressions for each layer of SG structure are given and rigorous coupled-wave equations are deduced. The numerical investigations for the diffraction spectra of SG by our theoretical and computer programs are in good agreement with the results of classical RCWA in the condition when a Sandwish grating is simplified to a classical one-layer grating. The calculations by our programs of another condition when a Sandwish grating is degenerated to a classical single planar structure also conform to the results of classical electromagnetic theory. The research results above indicate that the extended theoretical formula has backwards compatibility and is self-consistent with the classical theory.
文摘In this paper, the intensity distributions of the magnetic field in the proposed sandwich grating were studied. The results indicated that there were two apparent enhanced transmission peaks. The magnetic intensity distributions of these two peaks manifest that the narrow higher transmission enhancement peak was caused by guided mode resonance and the other wide low one was formed by surface plasmon resonance. The resonant wavelength was estimated by the momentum matching conditions of resonance.
